fix(HTML encoding): Use `<span>` instead of `<pre>` for text outputs
fix(HTML encoding): Use `<span>` instead of `<pre>` for text outputs

stencila/stencila,stencila/stencila,stencila/stencila,stencila/stencila,stencila/stencila,stencila/stencila,stencila/stencila